This disclosure relates to a display device capable of detecting an external proximity object, and in particular, to a display device with a touch detection function detecting touch events based on a change of an electrostatic capacitance, a control circuit, a driving method, and an electronic unit including the same.
In recent years, a display device capable of inputting information by mounting a contact detection device, which is a so-called touch panel, on a display device such as a liquid crystal display device, or integrating the touch panel and the display device, and displaying various button images and the like on the display device instead of typical mechanical buttons has attracted attention. The display device including such a touch panel does not require input devices such as a keyboard, a mouse, and a keypad, and therefore there is a tendency to expand the use of such a display device to portable information terminals such as mobile phones, in addition to computers.
As a method used in a touch detection device, some methods such as optical method and a resistance method exist. Particularly, for mobile terminals or the like, an electrostatic capacitance type touch detection device is expected which has a relatively simple configuration and is capable of achieving low power consumption. For example, in Japanese Unexamined Patent Application Publication No. 2009-244958, a display device in which a common electrode which is for display and is arranged originally for each display device is also used as one electrode of a pair of touch sensor electrodes, and the other electrode (touch detection electrode) is arranged to intersect the common electrode has been proposed. An electrostatic capacitance is formed between the common electrode and the touch detection electrode, and the electrostatic capacitance is changed in response to an external proximity object. The display device uses the change of the electrostatic capacitance to analyze a touch detection signal which appears in the touch detection electrode in response to application of touch detection drive signal to the common electrode, and detects the external proximity object. In the display device, display operation is performed by sequentially applying a drive signal to the common electrode to perform line-sequential scanning, and according to the drive signal, touch detection operation is performed by analyzing the touch detection signal which appears in the touch detection electrode with the period of the display scanning.